In a groundbreaking development that could revolutionize the energy sector, researchers have uncovered a novel method to enhance the performance of magnetic tunnel junctions (MTJs), a critical component in spintronic devices. The study, led by Qiaoxuan Zhang from the Department of Electrical Engineering and Automation at Hebei University of Water Resources and Electric Engineering in China, explores the impact of twisting an insulating barrier layer within a van der Waals heterostructure, potentially paving the way for more efficient and miniaturized spintronic applications.
Magnetic tunnel junctions are pivotal for various spintronic applications, including magnetic memory and sensors. The research team investigated the effects of rotating the hexagonal boron nitride (h-BN) layer within a van der Waals MTJ structure composed of graphene, 1T-VSe2, and h-BN. By employing first-principles calculations based on density functional theory (DFT) and the non-equilibrium Green’s function (NEGF) formalism, the team systematically analyzed the spin-dependent transport properties for 18 distinct rotational alignments of the h-BN layer.
The findings are striking. The tunneling magnetoresistance (TMR) ratio, a key metric for MTJ performance, exhibited dramatic variations depending on the twist angle of the h-BN layer. The TMR ratio ranged from 2328% to an astonishing 24,608%, with the maximum TMR occurring near a 52.4° twist angle. “The twist angle modifies the d-orbital electronic states of interfacial vanadium atoms in the 1T-VSe2 layers and alters the spin polarization at the Fermi level,” explained Zhang. “This governs the spin-dependent transmission through the barrier, providing an effective means to engineer the TMR and performance of van der Waals MTJs.”
The implications for the energy sector are profound. Spintronic devices, which leverage the spin of electrons rather than their charge, promise significant advancements in data storage, processing, and sensing technologies. By optimizing the TMR ratio through twist-angle engineering, researchers can enhance the efficiency and miniaturization of these devices, leading to more powerful and energy-efficient applications. “This research opens up new avenues for designing and optimizing spintronic devices,” added Zhang. “The ability to fine-tune the TMR ratio through rotational manipulation of the h-BN layer could lead to breakthroughs in magnetic memory and sensor technologies.”
The study, published in the journal ‘Nanomaterials’ (translated to ‘Nano Materials’ in English), highlights the potential of van der Waals heterostructures in the development of next-generation spintronic devices. As the energy sector continues to seek innovative solutions for efficient data storage and processing, this research offers a promising path forward. By harnessing the unique properties of two-dimensional materials and twist-angle engineering, the future of spintronics looks brighter than ever.